well the main difference gameplay-wise I can think up of is that in tf2 you should generally move a lot more than in csgo since the accuracy doesn't change at all regardless of whether your crouching or standing still or jumping or whatever and the weapons don't have weights
plus the different weapons have very differing stats and playstyles if you're into that kinda thing, imo it makes the game much more interesting, although you'll probably come to hate people who use certain ones